1. Field of the Invention
This invention relates to actuator systems and, more particularly, to a system having an output shaft that is driven by a motor through a planetary gear train.
2. Background Art
Geared rotary actuator systems are commonly used on aircraft controls. These actuators are often located in very tight areas such as within engine nacelles and leading and trailing edges of aircraft wings. Because there is a premium on space and weight in aircraft construction, and in the interest of reducing aerodynamic drag, designers of aircraft controls strive to minimize the size of the actuators therefor.
A conventional actuator typically includes an output shaft to be rotated, a drive motor and structure for coupling the drive to the output shaft for rotation thereof. One application for such an actuator system is to rotate a jet engine nozzle flap. The entire actuator system is contained within the engine nacelle and, heretofore, such systems have not been space efficient.
The principal problem with the above-described system is that the drive unit and the output shaft have occupied separate spaces. The amount of space occupied by the drive unit may be significant. The nacelle must be enlarged to enclose the drive motor, resulting in an undesirable increase in drag.